docstr: make sure note2freq(A4) == 440
docstr_tok: ["make","sure","note2freq","(","A4",")","==","440"]
code: def test_note2freq_under(self):
      "make sure note2freq(A4) == 440"
      if float_type == "float32":
          self.assertEqual(440, note2freq("A4"))
      else:
          self.assertLess(abs(note2freq("A4") - 440), 1.0e-12)
  
imports: from __future__ import unicode_literals
  from aubio import note2midi, freq2note, note2freq, float_type
  from numpy.testing import TestCase
  from _tools import parametrize, assert_raises, skipTest
label_desc: Use image node_id 2 for calling the note2freq_simple_test obj's underlying member method code with example usage: obj.test_note2freq_under() without return types